U.S. Pat. No. 3,442,087 describes a subsurface irrigation system which includes valve means for the distribution of water to moisten soil beneath the surface in which the system is embedded. A subsurface system has the advantage of not wasting a substantial percentage of water to evaporation. This invention is of an improved valve which may be utilized in such a system, i.e., a system which is composed of a plurality of parallel pipes each with a plurality of downwardly opening spaced holes therealong. The system is used for applying water beneath the surface so that the roots of the plants are conveniently moistened or fertilized. A problem has been the delivery of relatively similar amounts of water from each hole so that as a whole the water delivery in a given time period by the system in a field is not such as to overwater one portion excessively in relation to other portions of the field. This invention is of a flow control valve to be included in each of the holes of the pipes of the system.